[es6] Implement inner scope for functions with destructuring

src/scopes.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/bootstrapper.h"
 #include "src/messages.h"
 #include "src/parser.h"
@@ skipping 133 matching lines @@
                                           kCreatedInitialized);
   AllocateHeapSlot(variable);
 }
 
 
 void Scope::SetDefaults(ScopeType scope_type, Scope* outer_scope,
                         Handle<ScopeInfo> scope_info,
                         FunctionKind function_kind) {
   outer_scope_ = outer_scope;
   scope_type_ = scope_type;
+  is_declaration_scope_ =
+      is_eval_scope() || is_function_scope() ||
+      is_module_scope() || is_script_scope();
   function_kind_ = function_kind;
   scope_name_ = ast_value_factory_->empty_string();
   dynamics_ = nullptr;
   receiver_ = nullptr;
   new_target_ = nullptr;
   function_ = nullptr;
   arguments_ = nullptr;
   this_function_ = nullptr;
   illegal_redecl_ = nullptr;
   scope_inside_with_ = false;
@@ skipping 1192 matching lines @@
             isolate->factory()->arguments_string())) {
       return true;
     }
   }
   return false;
 }
 
 
 void Scope::AllocateStackSlot(Variable* var) {
   if (is_block_scope()) {
-    DeclarationScope()->AllocateStackSlot(var);
+    outer_scope()->DeclarationScope()->AllocateStackSlot(var);
   } else {
     var->AllocateTo(VariableLocation::LOCAL, num_stack_slots_++);
   }
 }
 
 
 void Scope::AllocateHeapSlot(Variable* var) {
   var->AllocateTo(VariableLocation::CONTEXT, num_heap_slots_++);
 }
 
@@ skipping 236 matching lines @@
   bool is_function_var_in_context =
       function_ != NULL && function_->proxy()->var()->IsContextSlot();
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS -
          2 * num_global_slots() - (is_function_var_in_context ? 1 : 0);
 }
 
 
 int Scope::ContextGlobalCount() const { return num_global_slots(); }
 }  // namespace internal
 }  // namespace v8